Alfredo Junior Paiola Albrecht

Seed quality of soybean produced with bioregulator management

The objective of this study was to evaluate the physiological and sanitary quality of soybean seeds treated with the growth regulator Stimulate®. Seeds of the cultivar BRS 246 RR were planted in October of crop years 2007/2008 and 2008/2009, in a randomized complete block design with four replications. The treatments were set out in a factorial, with a combination of seed treatment and the growth regulator (with and without 0.500 L.100 kg-1 bean) at five product dosages (0, 0.125, 0.250, 0.375 and 0.500 L ha-1) with foliar application at two developmental crop stages (V5 or R3). The application of Stimulate® positively altered seed quality, especially at the V5 stage.

Rates of Chlorimuron Applied in Glyphosate-Tolerant and Sulfonylurea-Tolerant Soybean

Susceptibility to chlorimuron varies according to soybean genotype. STS® (sulfonylurea-tolerant soybean) presents a high tolerance to some sulfonylureas; this feature is determined by semi-dominants alleles, Als1 and Als2. Experiments were conducted in the field for four seasons with two cultivars for season to evaluate the selectivity of chlorimuron rates in post-emergency (V4) of glyphosate-tolerant and sulfonylurea-tolerant soybean. Data analysis made it possible to infer that there was no significant effect on the productivity of the cultivars when they received application in post-emergency, of chlorimuron at the doses used (0, 15, 30, 45, 60, 75, and 90 g ai ha-1). The maximum recommended rate for non-STS cultivars of chlorimuron is 20 g ai ha-1, or 4.5 times less than the maximum rate employed in this study. The soybean cultivars CD 250 RR/STS, CD 236 RR/STS, CD 2630 RR/STS, and BMX Turbo RR/STS were tolerant to the application, in post-emergency (V4) of the herbicide chlorimuron, until the rate of 90 g ai ha-1.